Numerically controlled machine tool with automatic tool changing apparatus

ABSTRACT

Numerically controlled machine tool with automatic tool changing apparatus is capable of carrying diverse tools in an interrelated relationship. The tool changing apparatus comprises a tool magazine and carrying means for both taking a new tool from a predetermined first position of the tool magazine to a predetermined second waiting position thereof after normal turning of the tool magazine by two angular pitch and for carrying a previously used tool positioned at the second waiting position to the first position, and a tool transfer arm for simultaneously removing the previously used tool from the spindle and removing the new tool from the carrying means at the second position and next transferring the new tool to the spindle. The previously used tool is transferred from the tool transfer arm to the carrying means and then to the magazine at the first position after an inverse turning of the tool magazine by one angular pitch.

United States Patent 1191 i all of Japan Assignee:

[73] Toyoda Machine Works, Limited, Aichi-ken, Japan 22 Filed: Sept. 29,1969- [21] Appl. No.: 861,666

[30] Foreign Application Priority Data Sept. 30, 1968 Japan 43/71024[52] US. Cl. 29/568, 318/593 [51] Int. Cl. B23q 3/157 [58] Field ofSearch 29/568, 26, 33 D;

[56] References Cited UNITED STATES PATENTS 3,277,569 l0/ 1966 Veehoeven291568 3,451,125 6/1969 1 Lehmkuhl 29/568 3,516,149 6/1970 Mickas 29/5683,358,360 12/1967 Zankl et al 29/568 3,372,568 3/1968 bemelson 29/33 P3,449,822 6/1969 Launann et al... 29/568 3,580,133 5/1971, Berthi'cz90/11 R 3,125,796 3/1964 Brainard 29/26 Tomita et a1. Dec. 4, 1973 [5NUMERICALLY CONTROLLED MACHINE 3,209,221 9/1965 Puglsey et al 318/593 xTOOL WITH AUTOMATIC TOOL 3,276,116 10/1966 Stark 29/568 3,300,856 1/1967Daugherty 29/568 CHANGING APPARATUS 3,323,030 5/1967 lnaba et al....318/593 [75] Inventors: Tamaki Tomita, Okazaki-shi; Takesi 9 12/1967 D l29/5 8 Kusakabe, Kariya-shi; Mikishi 3,458,924 8/1969 Oslebo et al..29/568 K i td Nagoya shi; Tsum 3,492,717 2 1970 Seidel et al. 29/568Iwami both of 9/1970 Shotter 29/568 Kariyashh Kenzi Nomura; FOREIGNPATENTS OR APPLICATIONS Ymhikaz" San", 30th of Aichi-ken, 1,569,7296/1969 France 29/568 Primary Examiner-Andrew R. .luhas'z AssistantExaminer-Z. R. Bilinsky Attorney-Robert E. Burns and Emmanuel .I. Lobato[57] ABSTRACT Numerically controlled machine tool with automatic toolchanging apparatus is capable of carrying diverse tools in aninterrelated relationship. The tool changing apparatus comprises a toolmagazine and carrying means for both taking a new tool from apredetermined first position of the tool magazine to a predeterminedsecond waiting position thereof after normal turning of the toolmagazine by two angular pitch and for carrying a previously used toolpositioned at the second'waiting position to the first position, and atool transfer arm for simultaneously removing the previously used toolfrom the spindle and removing the new tool from the carrying means atthe second position and next transferring the new tool to the spindle.The previously used tool is transferred from the tool transfer arm tothe carrying means and then to the magazine at the first position afteran inverse turning of the tool magazine by one angular pitch.

30 Claims, 41 Drawing Figures United States Patent [191 [111 3,775,837Tomita et a1. [451 Dec. 4, 1973 w m M9 5 "sum cum-"2e ATTORNEYATENTEUBEn IQIs 3am 030;

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1. In a machining apparatus: a spindle head having a rotatably mountedspindle including thereon means for releasably holding a work tool; arotatable tool magazine removably storing a plurality of work toolshaving various weights; means mounting said spindle head and said toolmagazine for vertical reciprocal movement along respective verticalaxes; drive means for vertically reciprocating said spindle head alongsaid vertical axis; balancing means for counterbalancing the combinedweight of said tool magazine and spindle head; connecting meansinterconnecting said balancing means with both said tool magazine andspindle head and coaching with said balancing means for effectingcontinuously synchronous vertical movement of said spindle head and toolmagazine in response to vertical movement of said spindle head by saiddrive means, said connecting means comprising a pin having alongitudinal axis, a bracket pivotal about said longitudinal axis ofsaid pin, a first flexible member interconnecting said tool magazinewith said bracket at a portion thereof disposed on one side of saidvertical plane passing through said longitudinal axis, a second flexiblemember interconnecting said spindle head with said bracket at a portionthereof disposed on the other side of said vertical plane and saidbalancing means comprising force applying means connected to said pinfor applying a predetermined force to said pin counterbalancing thecombined weight of said tool magazine and spindle head whereby saidbracket undergoes pivotal movement about said pin as a function of theparticular weight of said tool magazine relative to the weight of saidspindle head; and tool transfer means operable when said tool magazineand spindle head are at any position along their respective verticalaxes for transferring a work tool from said tool magazine to saidspindle head and for transferring a work tool from said spindle head tosaid tool magazine.
 2. In a machining apparatus according to claim 1:wherein said force applying means comprises a dead weight suspended fromsaid pin.
 3. In a machining apparatus according to claim 1: wherein saidforce applying means comprises a cylinder, a piston slidably mounted insaid cylinder and having a piston rod connected to said pin, and fluidsupply means for supplying fluid at a predetermined pressure to saidcylinder to bias said piston in one direction with a force equal to saidpredetermined force.
 4. In a machining apparatus according to claim 3:including means mounting said cylinder for pivotal movement tofacilitate the synchronous movement of said tool magazine and spindlehead.
 5. A numerically controlled machine tool comprising: a base; afirst table slidably mounted on said base for sliding motion along afirst axis; a first feed motor connected to said first table operable toslidably feed same along said first axis; a second table slidablymounted on said first table for sliding motion along a second axisextending crosswise to said first axis; a second feed motor connected tosaid second table operable to slidably feed same along said second axis;a spindle head; means mounting said spindle head for sliding movementalong a third axis perpendicular to both said first and second axes; athird feed motor connected to said spindle head operable to slide samealong said third axis; a spindle rotatably supported by said spindlehead and having means thereon for interchangeably holding diverse toolsto be used for performing respective machining operations; a toolmagazine having a plurality of tool clamping means thereon for removablystoring a plUrality of diverse tools in a predetermined array; meansmounting said tool magazine for both sliding movement along a fourthaxis extending parallel to said third axis and rotational movement toindividually position each of the diverse tools in a first tool changeposition; intermediate tool transfer means for transferring a desiredtool from its first tool change position on said tool magazine to asecond tool change position adjacent said spindle and for transferring aused tool carried by said spindle from said second tool change positionto said first tool change position; tool magazine indexing meanscoacting with said tool magazine for indexing the desired tool to saidfirst tool change position; tool transfer means for interchanging theused tool held by said spindle with the desired tool held by saidintermediate tool transfer means when same has transferred the desiredtool to said second tool change position; balancing means forsynchronizing the movement of said tool magazine along said fourth axiswith the movement of said spindle head along said third axis comprisinga pin, a bracket pivotally connected to said pin, a first flexiblemember interconnecting said spindle head with said bracket, a secondflexible member interconnecting said tool magazine with said bracket,and wherein the connected positions of said tool magazine and saidspindle head define balanced positions with respect to moments takenabout said pin; and control means for controlling the tool changeoperation between said tool magazine and said spindle and the motions ofsaid three feed motors according to a predetermined program.
 6. Anumerically controlled machine tool according to claim 5, wherein saidplurality of tools are arranged in said predetermined array in theirsequence of utilization for performing machining operations; and whereinsaid tool magazine indexing means comprises a drive motor for rotatingsaid tool magazine, an indexing plate connected to and rotationallydriven by said drive motor, a plunger engageable with said indexingplate for substantially restricting rotational movement of said indexingplate, detecting means for detecting the angular displacement of saiddrive motor and providing corresponding output signals, and a countercircuit for generating control signals in response to output signalsfrom said detecting means when said tool magazine angularly displaces bytwo pitch angular distance between two adjacent tool clamping means inone direction and when said tool magazine angularly displaces by onepitch in a reverse direction, whereby said plunger is actuated inresponse to said control signals to engage with said indexing plate forcontrolling said drive motor to stop the angular displacement of saidtool magazine.
 7. A numerically controlled machine tool according toclaim 5, wherein said tool magazine comprises: a rotatable shaftconnected to said tool magazine indexing means; a magazine disc securedto said shaft; and wherein said plurality of tool clamping meanscomprise a plurality of tool clamp devices mounted on a peripheralportion of said magazine disc with equiangular distance between oneanother, each of said tool clamp devices comprising a stationary pawlsecured to said magazine disc, a pivotal pawl pivotably mounted on saidmagazine disc cooperative with said stationary pawl to hold a tooltherebetween, and resilient means for urging said pivotal pawl towardssaid stationary pawl to clamp a tool therebetween, and clamp releasingmeans engageable with said pivotal pawl for releasing a tool from saidtool clamp device.
 8. A numerically controlled machine tool according toclaim 7, wherein said pivotal pawl has a clamp portion at one endthereof and an L-shaped portion engageable with said resilient means atone surface thereof to be urged to clamp a tool and engageable with saidclamp releasing means at the opposite surface thereof to release a toolpositioned at said first tool change position.
 9. A numericallycontrolled machinE tool according to claim 5, wherein said tool magazinecomprises a magazine slide mounted for slidable movement, a magazineframe pivotably connected to said magazine slide and latch means foreffecting releasable latching engagement between said magazine frame andmagazine slide, a shaft turnably supported by said magazine frame, and amagazine disc secured to said shaft, whereby said magazine frame may beangularly displaced a predetermined extent when said latch means isoperated to release said latching engagement.
 10. A numericallycontrolled machine tool according to claim 5, wherein said intermediatetool transfer means comprises drive means mounted on said spindle head;and an intermediate transfer arm connected to said drive means at oneend thereof, said intermediate transfer arm being provided at the otherend thereof with a pair of clamp fingers for clamping said tool in itsshank portion and arranged in the longitudinal direction of said toolfor engaging with said shank portion and a finger operating means foralternatively opening and closing said clamp fingers, said pair offingers being opened by said finger operating means in a radialdirection with respect to a circular path of said tool transfer meanswhen said intermediate transfer arm arrives at said second tool changeposition, whereby the opened fingers allow the free rotation of saidtransfer means loaded with tools.
 11. A numerically controlled machinetool according to claim 5, wherein said tool transfer means comprises ahydraulic reciprocating actuator comprising a cylinder secured to saidspindle head a piston slidably mounted in said cylinder, means defininga cylindrical bore coaxially formed in said piston, a rotary actuatordisposed in said piston, a rotary shaft rotatably and coaxially disposedin said cylindrical bore and connected to be rotated by said rotaryactuator, a pair of transfer arms symmetrically and rigidly secured to aprojected end portion of said rotary shaft, each transfer arm beingprovided with a tool clamping means comprising a pair of turnablefingers and a hydraulic actuator for alternatively opening and closingsaid turnable fingers.
 12. A numerically controlled machine toolaccording to claim 11, wherein said rotary hydraulic actuator comprisesa partition secured in said cylindrical bore of said piston, a rotormember rotatably mounted in said cylindrical bore and connected to saidrotary shaft, and a turnable rotor member disposed between saidpartition and said rotor member to turn to a restricted extent in saidcylindrical bore.
 13. A numerically controlled machine tool according toclaim 5, further comprising spindle indexing means including stop meansfor stopping said spindle at a predetermined angular position, andprecise indexing means comprising a shaft rotatably disposed in saidspindle head and having means therein defining a recess disposed in apredetermined relationship with respect to said spindle, and meansincluding a gear train and an indexing pin which reciprocates to engageand disengage with said recess for connecting said shaft with saidspindle, whereby the stopped spindle is precisely indexed when saidindexing pin is engaged with said recess.
 14. A numerically controlledmachine tool according to claim 5, wherein each of said three feedmotors comprises a hydraulic pressure motor, a servo-valve forcontrolling the pressurized liquid supplied to said hydraulic pressuremotor, an electric digital motor having a rotary output controlled by anelectric digital input signal and connected to said servo-valve, and anelectric analog motor rotatable at a higher speed of rotation than saidelectric digital motor and connected to said servo-valve, whereby saidpressurized liquid is controlled in accordance with the rotation of oneof said digital and analog electric motors.
 15. A numerically controlledmachine tool according to claim 5, wherein said balancing means furthercomprises a hydraulic balancing actuator.
 16. A numerIcally controlledmachine tool according to claim 5, wherein said balancing means furthercomprises a dead weight.
 17. A numerically controlled machine toolaccording to claim 5, wherein each of said three feed motors comprises,driving means, an electric digital motor and an electric analog motorconnected with said driving means, and a position coder connected withsaid driving means to generate coarse pulses in accordance with therotation thereof; and wherein said control means includes a pulsegenerator for generating fine pulses to energize said digital motor, andcontrol circuits for controlling said digital and analog motors inaccordance with said coarse pulses, whereby said driving means isactuated by said digital motor at a low speed and when a predeterminednumber of pulses are generated by said position coder, the driving ofsaid driving means is changed by said control circuits from said digitalmotor to said analog motor to attain a high speed rotation.
 18. Anumerically controlled machine tool according to claim 5, wherein eachof said three feed motors comprises, driving means, an electric digitalmotor and an electric analog motor connected with said driving means,and a position coder connected with said driving means to generatecoarse pulses in accordance with the rotation thereof; and wherein saidcontrol means includes a pulse generator for generating fine pulses toenergize said digital motor, and control circuits for controlling saiddigital and analog motors in accordance with said coarse pulses, wherebysaid driving means is actuated by said analog motor at a high speed andwhen a predetermined number of coarse pulses are generated by saidposition coder, the driving of said driving means is changed by saidcontrol circuits from said analog motor to said digital motor to attaina low speed rotation.
 19. A numerically controlled machine toolaccording to claim 18, wherein said control means is further providedwith means for generating numerical information having higher digits andlower digits with respect to each of said feed motors, high digitcounters for presetting said higher digits, low digit counters forpresetting said lower digits, and means connecting said low digitcounters with said fine pulse generators and said high digit counterswith said position coder.
 20. A numerically controlled machine toolcomprising: a base; an upright column mounted on said base and havingconnected thereto first and second guide means; a spindle headvertically slidably mounted on said first guide means; a spindlerotatably supported by said spindle head and having means thereon forinterchangeably holding diverse tools required for machining operations;a tool magazine removably storing a plurality of diverse tools andvertically slidably mounted on said second guide means; means mountingsaid tool magazine for rotation in a vertical plane for indexing adesired tool to a first tool change position thereon; hydraulicbalancing means including a first flexible member connected with saidspindle head and a second flexible member connected with said toolmagazine for hydraulically developing a force substantially equal to andopposing the total weight of said spindle head and tool magazine tobalance the weights thereof and including means for synchronizing thevertical movement of said tool magazine with the vertical movement ofsaid spindle head; intermediate tool transfer means for transferring atool positioned in said first tool change position to a second toolchange position adjacent to said spindle and for transferring a tool insaid second tool change position to said first tool change position;tool transfer means for interchanging a tool held by said spindle with atool held in said second tool change position; and means mounting saidintermediate tool transfer means and tool transfer means for rotation insubstantially the same plane as said vertical plane; in which a tool isindexed in said tool magazine; whereby said intermediate tool trAnsfermeans and said tool transfer means are operable when said tool magazineand spindle are at any position along their respective vertical axes fortransferring a tool in such manner that the tool is transferred fromsaid tool magazine to said spindle within the same vertical plane whilekeeping the tool in the same attitude it had when stored in said toolmagazine.
 21. A numerically controlled machine tool according to claim20, wherein said balancing means comprises a pin, a bracket movablyconnected to said pin and also connected with said tool magazine andspindle head by means of respective ones of said first and secondflexible members, and wherein the connected positions of said toolmagazine and said spindle head with said bracket are defined by balancedpositions with respect to moments taken about said pin.
 22. Anumerically controlled machine tool comprising: a base; an uprightcolumn mounted on said base and having connected thereto first andsecond guide means; a spindle head vertically slidably mounted on saidfirst guide means on said upright column; a spindle rotatably supportedby said spindle head and having means thereon for interchangeablyholding diverse tools required for machining operations, said diversetools each having a tool holder provided with a shank portion and twoflange portions; a tool magazine removably storing a plurality ofdiverse tools and vertically slidably mounted on said second guidemeans; means mounting said tool magazine for rotation in a verticalplane for indexing a desired tool to a first tool change positionthereon; balancing means including flexible members connected with saidspindle head and said tool magazine, and hydraulic means forhydraulically developing a force applied to said tool magazine andspindle head for balancing the total weights thereof; connecting meansconnecting said flexible members with said hydraulic means and coactingtherewith for effecting continuously synchronous vertical movement ofsaid tool magazine and spindle head in response to vertical movement ofsaid spindle head; intermediate tool transfer means engageable with atool shank portion for transferring a desired tool with said shankportion being engaged thereby from said first tool change position to asecond tool change position adajcent to said spindle; tool transfermeans on said spindle head engageable with the two flange portions of atool to interchange a used tool held by said spindle with said desiredtool held in said second tool change position; and means mounting saidintermediate tool transfer means and tool transfer means for rotation insubstantially said vertical plane; whereby said desired tool istransferred in substantially the same plane as said vertical movementplane from said tool magazine to said spindle while the tool ismaintained in the same attitude it had when stored in said toolmagazine.
 23. A numerically controlled machine tool according to claim22, wherein said intermediate tool transfer means comprises drive meansmounted on said spindle head, an intermediate transfer arm connected tosaid drive means at one end thereof, said intermediate transfer armbeing provided at the other end thereof with a pair of clamp fingersarranged in the longitudinal direction of said tool holder for engagingwith said shank portion, finger operating means for alternativelyopening and closing said clamp fingers, and wherein said pair of fingersare opened by said finger operating means in a radial direction withrespect to said magazine disc when said intermediate transfer armarrives at said first tool change position.
 24. A numerically controlledmachine tool according to claim 22, wherein said tool transfer meansincludes means for transferring a tool along a circular path; saidintermediate tool transfer means comprises drive means mounted on saidspindle head, and an intermediate transfer arm connected at one end tosaid drive means and being provided at the other end with a pair ofclamp finGers arranged in the longitudinal direction said tool holderand engageable with said shank portion; finger operating means foralternatively opening and closing said clamp fingers alternatively,whereby said pair of fingers are opened by said finger operating meansin a radial direction with respect to said circular path of said tooltransfer means when said intermediate transfer arm arrives at saidsecond tool change position.
 25. A numerically controlled machine toolcomprising: a base; an upright column mounted on said base and havingconnected thereto first and second guide means; a spindle headvertically slidably mounted on said first guide means; a spindlerotatably supported by said spindle head and having means thereon forinterchangeably holding diverse tools required for machining operations;a tool magazine removably storing a plurality of diverse tools andvertically slidably mounted on said second guide means; means mountingsaid tool magazine for movement to effect indexing of a desired tool toa first tool change position along a first circumference path; balancingmeans including a first flexible member connected with said spindle headand a second flexible member connected with said tool magazine forsynchronizing the vertical movement of said tool magazine with thevertical movement of said spindle head; tool transfer means forinterchanging a tool between a second tool change position and saidspindle along a second circumference path; and intermediate transfermeans for transferring a tool from said first tool change position tosaid second tool change position along an arc path terminating at saidfirst and second tool change positions, said intermediate transfer meansbeing substantially tangential at said first and said second tool changepositions with said first and second circumference paths, respectively.26. A numerically controlled machine tool according to claim 25, whereinsaid balancing means comprises hydraulic means for hydraulicallydeveloping a force substantially equal to and opposing the total weightof said tool magazine and said spindle head to support the weightsthereof, and connecting means connecting said first and second flexiblemembers with said hydraulic means for effecting continuously synchronousvertical movement of said tool magazine and spindle head in response tovertical movement of said spindle head.
 27. A numerically controlledmachine tool according to claim 26, wherein said connecting meanscomprises a bracket pivotally connected to said hydraulic means and alsoconnected to said first and second flexible members, and wherein theconnected positions of said first and second flexible members aredefined by balanced positions with respect to moments taken about thepivotal point of said bracket.
 28. A numerically controlled machine toolaccording to claim 25, wherein said balancing means comprises asuspended weight counterbalancing the total weight of said tool magazineand said spindle head, and connecting means connecting said first andsecond flexible members with said weight for effecting continuouslysynchronous vertical movement of said tool magazine and spindle head inresponse to vertical movement of said spindle head.
 29. A numericallycontrolled machine tool according to claim 25, wherein said intermediatetransfer means is provided at one end thereof with a pair of relativelymovable clamp fingers, and finger operating means for alternativelyopening and closing said clamp fingers in radial directions with respectto said first and second circumference paths when said intermediatetransfer means arrives at said first and second tool change positionsrespectively.
 30. In a machining apparatus having a spindle headincluding a rotatably mounted spindle having means for releasablyholding a tool: a rotatable tool magazine removably storing a pluralityof tools; means mounting said spindle head and tool magazine forvertical reciprocal movement along respective vertical axes; drive meansFor vertically reciprocating said spindle head along said vertical axis;first and second flexible members respectively connected to said spindlehead and tool magazine; hydraulic force applying means for applying aforce to said tool magazine and spindle head effective to support thetotal weight of said tool magazine and spindle head, said hydraulicforce applying means including a hydraulic cylinder, a piston slidablymounted in said cylinder, a piston rod, and fluid supply means forsupplying pressurized hydraulic fluid to said cylinder to bias saidpiston in one direction with a force equal to the total weight of saidtool magazine and spindle head; connecting means connecting said firstand second flexible members to said hydraulic force applying means andcooperative therewith to effect continuously synchronous verticalmovement of said tool magazine and spindle head in response to verticalmovement of said spindle head by said drive means, said connecting meanscomprising a pin connected to said piston rod, a bracket pivotallyconnected to said pin and connected to said spindle head and toolmagazine by way of respective ones of said first and second flexiblemembers, and wherein the connected positions of said tool magazine andsaid spindle head with said bracket are defined by a balanced positionwith respect to moments taken about said pin; and tool transfer meansoperable when said tool magazine and spindle head are at any positionalong their respective vertical axes for transferring a tool from saidtool magazine to said spindle and for transferring a tool from saidspindle to said tool magazine.